1. Field of the Invention
The present invention mainly relates to a release agent supplying member, a release agent supplying apparatus each for supplying release agent to a subject to be coated and a fixing apparatus using it.
2. Description of the Related Art
In a fixing apparatus which heats and pressurizes a toner image formed on recording material by means of a heat roller and a pressure roller thereby to fix the toner image on the recording material, release agent is, generally, coated on the surface of the heat roller so as to improve the releasing characteristics between the heat roller and the toner image.
Conventionally, there have been proposed various types of release agent supplying apparatuses used in such a kind of fixing apparatus. As one mode of such a release agent supplying apparatus, there is known a release agent supplying apparatus which includes, as shown in FIG. 6, a release agent tank 17 for receiving release agent therein, a pump 18 for drawing the release agent within the release agent tank 17, a release agent supplying member 19 having release agent discharge portions 19a for discharging the release agent drawn from the release agent tank 17, and a release agent coating roller 14 for receiving the release agent 20 flowing down on the upper surface of the release agent supplying member 19.
In such a configuration, the release agent 20 is supplied from the tank 17 through the pump 18. The release agent 20 drawn by the pump 18 is discharged from the release agent discharge portions 19a which are provided at the release agent supplying member 19 and formed by a large number of through holes. The release agent 20 thus discharged is wiped with the release agent coating roller 14 through the rotation thereof, then the release agent 20 thus transferred to the surface of the release agent coating roller 14 is coated on the surface of the heat roller 11a.
In the aforesaid configuration of the conventional release agent supply apparatus, at the time of supplying the release agent 20 to the heat roller 11a, the release agent 20 discharged from each of the release agent discharge portions 19a flows down on the upper surface of the release agent supplying member in a stripe fashion as shown in FIG. 7. Accordingly, an amount of the release agent coated on the heat roller 11a becomes uneven along the axial direction thereof due to such phenomenon that the liquid level of the release agent 20 on the upper surface of the release agent supplying member 19 becomes uneven in accordance with the arrangement of the release agent discharge portions 19a as shown in FIG. 8. Another phenomenon which creates an uneven distribution of releasing agent along the heat roller 11a is that several flows of the release agent are joined to form a single flow on the upper surface of the release agent supplying member since the flows of the release agent fluctuate.
When the fixing process is carried out when an uneven amount of the release agent is coated on the heat roller, gloss of a toner image after the fixing process may become uneven where an excessive amount of release agent is coated on the heat roller. Further, there appears a so-called offset phenomenon wherein the toner image adheres to the heat roller 11a at the portion where an insufficient amount of the release agent is coated such that suitable releasing characteristics are not obtained at such a portion on the surface of the heat roller 11a. Accordingly, there arises a problem that the printing quality is degraded.